Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already establish read-only, idempotent, non-destructive, open-world behavior, so the bar is lower. The description still adds real context beyond them: the returned fields (model IDs, shutdown dates, replacements, sources) and the sort order, which the annotations do not convey. It stops short of disclosing default filter behavior or result freshness.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two tightly packed sentences, front-loaded with the returned content before the filtering options. The 'calendar' framing is slightly decorative but costs little, and there is no redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description carries the return-value burden and does so by naming the fields and ordering. Combined with annotations covering the safety profile, an agent has enough to call it, though the defaults for unfiltered calls and include_retired remain unstated.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 67%: within_days and include_retired are self-documented, while vendor has only an enum with no prose. The description adds a plain-language gloss for vendor and within_days ('how many days ahead to look') but says nothing about include_retired or the default when no filters are passed. Baseline 3 is appropriate at this coverage.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description gives a concrete resource and verb-like framing ('The AI model retirement calendar: model IDs with their shutdown dates, replacements and sources') and states the ordering ('soonest first'). It never distinguishes itself from the close sibling find_retired_models, which an agent could easily confuse it with.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It mentions what can be filtered ('Filter by vendor or by how many days ahead to look'), which implies usage, but gives no when-to-use/when-not guidance and no routing against find_retired_models, get_migration_guide, or lookup_model.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.